The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
An environmentally friendly vehicle, which uses an electric motor as a drive source, such as, for example, a hybrid vehicle or an electric vehicle, generally uses, for example, a high-voltage battery as an energy source for driving the electric motor, and also uses power conversion parts, i.e. an inverter for providing a voltage to the motor and a low DC-DC converter (LDC) for realizing a vehicle voltage of 12 V.
Here, the inverter is provided between the electric motor and the high-voltage battery to convert the DC voltage of the high-voltage battery into a three-phase AC voltage and provide the same to the motor.
The main purpose of conventional electric vehicles is short-distance driving and city driving, and thus they usually feature relatively low output models of about 100 kW. That is, the power source of such an electric vehicle is generally a single motor for the front wheels because the electric vehicle does not need a high output, and thus the inverter for supplying current to the motor is also provided to correspond to an output within a relatively small range.
However, a variety of electric vehicles including, for example, sports-car-type and SUV-type electric vehicles, have recently been developed, and thus output specifications desired for the electric vehicles have diversified. It is impossible to satisfy an increased number of output specifications using only a single motor because of limitations on the size and weight of the motor, and thus an electric vehicle model in which a plurality of motors is provided for the front wheels and the rear wheels is being developed. Therefore, specifications of the inverter, which supplies current to the motor, have diversified. For example, when a 200 kW motor is provided on the front wheels and a 300 kW motor is provided on the rear wheels, the same inverter has difficulty in handling the two motors at the same time.
Meanwhile, the inverter, which has a planar structure, is configured such that a power module, a capacitor, and an LDC are disposed on the bottom surface of a housing, and a control board is disposed on the upper end thereof. A cooling path, along which cooling water flows, is formed below the power module and the LDC, which generate a large amount of heat, in order to inhibit or prevent, for example, deterioration in performance or damage to elements due to excessive heat.
A general inverter converts current using a single power module, and needs to use a high-output power module or to have an increased number of power modules in order to have increased output. It is difficult to realize high output of a predetermined value due to the properties of a switching element constituting the power module, and thus most inverters adopt the parallel connection of a plurality of power modules in order to deal with high-output specifications. However, because the housing and the cooling path need to be changed when the number of power modules is increased, the existing inverter concept may not be maintained and it is desired to develop a new inverter.
Accordingly, the expense and time taken to develop inverters that meet respective output specifications may be increased, and there is demand for a commonly usable structure capable of varying the output of an inverter.
The matters disclosed in this section is merely for enhancement of understanding of the general background of the present disclosure and should not be taken as an acknowledgment or any form of suggestion that the matters form the related art already known to a person skilled in the art.